Additive manufacture-assisted method for making structural elements having controlled failure characteristics

Abstract

A process for making a layered multi-material structural element having controlled mechanical failure characteristics. The process includes the steps of: supplying a cementitious layer and forming a polymer layer on the cementitious layer by additive manufacture such that the polymer layer has a first thickness and the cementitious layer has a second thickness, wherein the polymer layer comprises a polymer and the cementitious layer comprises a cementitious material; and allowing the polymer from the polymer layer to suffuse into the cementitious layer for a period of time to obtain a suffused zone in the cementitious layer such that the suffused zone has a third thickness that is less than half the second thickness.

We claim: 
     
       1. A process for making a layered structural element having controlled mechanical failure characteristics, the process comprising the steps of:
 forming a sacrificial mold by additive manufacturing, the sacrificial mold having a negative geometric contour that defines a positive geometric void; 
 supplying a cement slurry and filling the positive geometric void of the sacrificial mold with the cement slurry such that the cement slurry contacts the negative geometric contour directly and forms a positive geometric void that fits at least a portion of the negative geometric contour of the sacrificial mold; 
 curing the cement slurry to form a cement-mold composite comprising the sacrificial mold and a cured cement shape such that a suffused zone is formed where the cement slurry and the cured cement shape meet; and 
 partially dissolving the sacrificial mold from the cement-mold composite such that a portion of the sacrificial mold remains adhered to the cured cement shape, and the structural element is obtained. 
 
     
     
       2. The process of  claim 1 , wherein the positive geometric void of the structural element has a shape that comprises a schwarzite structure. 
     
     
       3. The process of  claim 1 , wherein the sacrificial mold comprises a water-soluble polymer. 
     
     
       4. The process of  claim 1 , wherein the sacrificial mold comprises a polymer selected from the group consisting of polyvinyl alcohol, polyvinylpyrrolidone, polylactic acid, and combinations of the same. 
     
     
       5. The process of  claim 1 , wherein the portion of the sacrificial mold that remains adhered to the cured cement shape has a uniform thickness between 10 and 1,000 micrometers. 
     
     
       6. The process of  claim 1 , wherein the step of curing the cement slurry includes allowing the cement slurry to cure for a period of time between two hours and seven days. 
     
     
       7. The process of  claim 1 , wherein the step of partially dissolving the sacrificial mold is carried out using an aqueous solvent.